Very fun. Getting to play with all the marvel characters can keep you entertained for hours. The story is decent and funny. I have a 6 year old and it is nice to have a game he can play too. He can spend hours stealing cars GTA style and crashing them, laughing the whole time. The only complaints I have is the flying controls could be much tighter. If you are playing two player and a cut scene is tripped by one player it was go full screen, even if the other play is in a race and the timer will keep counting down while you can't move. If you are flying and the other character goes through a door you will be in the same place you were when they went through to door but will suddenly be facing the same direction the other player is.
The controls are kind of a pain in the butt. I'm also one of those people that play with the Y axis on inverted. So I could have rated the game more if I wasn't constantly dying from a mistake I made due to me wanting to go one direction but I would go another.